ASTM C773-88(1999)

Standard Test Method for Compressive (Crushing) Strength of Fired Whiteware Materials

SCOPE
1.1 This test method covers two test procedures (A and B) for the determination of the compressive strength of fired whiteware materials.  
1.2 Procedure A is generally applicable to whiteware products of low- to moderately high-strength levels (up to 150 000 psi or 1030 MPa).  
1.3 Procedure B is specifically devised for testing of high-strength ceramics (over 100 000 psi or 690 MPa).
1.4 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 09-Oct-1999
• ICS: 81.060.20 - Ceramic products
• Technical Committee: C21 - Ceramic Whitewares and Related Products
• Drafting Committee: C21.03 - Methods for Whitewares and Environmental Concerns

Relations

• Replaced By: ASTM C773-88(2006) - Standard Test Method for Compressive (Crushing) Strength of Fired Whiteware Materials
• Effective Date: 15-Feb-2006
• Referred By: ASTM C1424-15(2019) - Standard Test Method for Monotonic Compressive Strength of Advanced Ceramics at Ambient Temperature
• Effective Date: 10-Oct-1999
• Referred By: ASTM D116-86(2020) - Standard Test Methods for Vitrified Ceramic Materials for Electrical Applications
• Effective Date: 10-Oct-1999

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn. Contact ASTM
International (www.astm.org) for the latest information.
Designation:C773–88(Reapproved 1999)
Standard Test Method for
Compressive (Crushing) Strength of Fired Whiteware
Materials
This standard is issued under the fixed designation C 773; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 4.2 Spherical Bearing Block—In vertical testing machines,
the spherical bearing block shall be spring suspended from the
1.1 This test method covers two test procedures (A and B)
upper head of the machine in such a manner that the upper
for the determination of the compressive strength of fired
platen of the machine (lower face of the spherical bearing
whiteware materials.
block) remains in a central position (spherical surfaces in full
1.2 Procedure A is generally applicable to whiteware prod-
contact) when not loaded. The spherical surfaces shall be well
ucts of low- to moderately high-strength levels (up to 150 000
lubricated, and the center of curvature shall lie on the lower
psi or 1030 MPa).
face of the platen. The diagonal or diameter of the platen shall
1.3 Procedure B is specifically devised for testing of high-
be only slightly greater than the diagonal of the 1 ⁄2-in.
strength ceramics (over 100 000 psi or 690 MPa).
(38.1-mm) square contact blocks to facilitate accurate center-
1.4 This standard does not purport to address all of the
ing of the specimens.
safety concerns, if any, associated with its use. It is the
4.3 Contact Blocks—Cold-rolled steel contact blocks shall
responsibility of the user of this standard to establish appro-
be used between the test specimen and the platens of the
priate safety and health practices and determine the applica-
1 5
machine. These blocks shall be 1 ⁄2 in. (38.1 mm) square by ⁄8
bility of regulatory limitations prior to use.
to ⁄4 in. (15.9 to 19.1 mm) thick, and the contact faces shall be
2. Referenced Documents surface ground until plane and parallel. The contact blocks
shall be resurfaced, if necessary, after each strength test, and
2.1 ASTM Standards:
may be reused only so long as the thickness remains over ⁄2 in.
E 4 Practices for Force Verification of Testing Machines
(12.7 mm). If the contact block is cracked during testing, it
E 6 Terminology Relating to Methods of Mechanical Test-
shall be replaced.
ing
4.4 Cushion Pads—Cushion pads shall be used between the
E 165 Test Method for Liquid Penetrant Examination
test specimens and the contact blocks to aid in distributing the
3. Significance and Use
load. New cushion pads shall be used for each specimen.
Suitable materials for cushion pads, selected in accordance
3.1 Resistance to compression is the measure of the greatest
with the compressive strength range of the material being
strength of a ceramic material. Ideally, ceramics should be
tested, are shown in the following table:
stressed this way in use. This test is a measure of the potential
Compressive Strength Range, psi (MPa) Cushion Pad
load-bearing usefulness of a ceramic.
5000 to 50 000 incl (34.5 to 345) blotting paper, ⁄64 in. (0.4 mm) thick
PROCEDURE A
Over 50 000 to 150 000 incl (345 to mild steel, ⁄32 in. (0.8 mm) thick (65
1030.0) HRB max)
4. Apparatus
5. Procedure
4.1 Testing Machine—Any testing machine conforming to
Practices E 4 and to the requirements for speed of testing
5.1 Dye-check specimens in accordance with Test Method
prescribed in Sections 5 and 12 of this test method, may be E 165 before testing. Discard any pieces exhibiting cracks or
used.
flaws visible to the unaided eye.
5.2 Clean the test specimens with a suitable solvent after
grinding and immerse in an ultrasonic bath filled with hot
This method is under the jurisdiction of ASTM Committee C-21 on Ceramic
detergent solution. Then rinse specimens in hot water, dry at
Whitewares and Related Products and is the direct responsibility of Subcommittee
110 6 2°C (230 6 4°F) for 2 h and cool to room temperature
C21.03 on Test Methods for Whiteware Properties.
Current edition approved Sept. 30, 1988. Published November 1988. Originally in a desiccator.
published as C 773 – 74 to replace C 407 and C 528. Last previous edition
C 773 – 88 (1994).
Annual Book of ASTM Standards, Vol 03.01.
Annual Book of ASTM Standards, Vol 03.03.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn. Contact ASTM
International (www.astm.org) for the latest information.
C773
5.3 Carefully center the specimen in the machine between
Single-operator component 1.50 % of the average
Between-laboratory component 8.80 % of the average
the contact blocks. Place an appropriate guard around the
specimen to contain flying fragments at failure; eye protection
8.2 Critical Differences—For the components of variance
should be used by the operator.
reported in 8.1, two averages of observed values should be
5.4 Apply the load continuously and without impact shock
considered significantly different at the 95 % probability level
until ultimate failure. The rate of loading to be used shall
if the difference equals or exceeds the following critical
depend on the compressive strength of the material being
differences listed below:
tested, as shown in Table 1. A
Critical Difference, % of Grand Average
Number of Observa- Single-Operator Between-Laboratory
tions in Each Average Precision Precision
6. Calculation
10 4.16 24.40
6.1 Calculate the compressive strength of each specimen as
A
follows: The critical differences were calculated using t 5 1.960 which is based on
infinite degrees of freedom.
C 5 P/A (1)
8.3 Confidence Limits—For the components of variance
noted in 8.1, single averages of observed values have the
where:
following 95 % confidence limits:
C 5 compressive strength of the specimen, psi or MPa;
Width of 95 % Confidence Limits, Percent of the
P 5 total load on the specimen at failure, lbf or N; and
A
Grand Average
A 5 calculated area of the bearing surface of the specimen,
Number of Observa- Single-Operator Between-Laboratory
2 2
in. or mm .
tions in Each Average Precision Precision
10 62.94 617.26
7. Report
A
The confidence limits were calculated using t 5 1.960 which is based on
7.1 Report the following information:
infinite degrees of freedom.
7.1.1 The procedure used,
8.4 Bias—Nostatementonbiasisbeingmadeduetolackof
7.1.2 Type of testing machine (hydraulic or screw),
an accepted standard reference material.
7.1.3 Material and size of contact blocks or of cushioning
materials, 9. Test Specimens
7.1.4 Description of material being tested (Note 1),
9.1 Preparation—The test specimens shall be right cylin-
7.1.5 Rate of loading,
ders. They may be formed and matured for the purpose of
7.1.6 Number of specimens tested,
compression testing, or they may be cut from
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